JPH08132416A - Press forming method for cement formed matter - Google Patents

Abstract

PURPOSE: To realize the forming of forming stock without being cut in the spreading of the material at pressing by a method wherein plate-like stock is transferred and placed onto the desired position of a bottom mold by moving a belt conveyor in a direction opposite to the delivery direction of the plate-like stock by nearly the same speed as the conveying speed of the plate-like stock. CONSTITUTION: Cement-based composition is delivered by the amount in proportion to the weight of a formed matter from the deliverying port of a stock feeder 5 and then cut with a cutter P in order to obtain plate-like stock 8. By extending the piston 11 of a hydraulic cylinder 10, a belt conveyor 6 is positioned above a bottom mold 4. As the plate-like stock is delivered out of the belt conveyor 6 through the rotation of the belt conveyor 6, the piston 11 is retracted with the same speed as the delivering speed of the plate-like stock 8 so as to get back the belt conveyor b to the former position of the delivery port of the stock feeder 5. Thus, the plate-like stock 8 is transferred onto the bottom mold 4 under the state that the stock 8 deforms by its own weight along the mold surface 41 of the bottom mold 4. Next, by lowering a top mold 3, the stock is pressed under the predetermined pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for press-molding a cement molded product.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a cement molded product such as a straight roof tile by press molding, Japanese Patent Publication No.
Japanese Patent Application No. 4-144266, Japanese Patent Application No. 3-1266 filed by the applicant of the present invention.
The method disclosed in 79290 has already been proposed.

That is, in the former method, the upper die is provided at the lower end of the high-pressure press piston that moves up and down, and the upper die is provided with a vacuum suction hole for water squeezing and conveying, and a wire net and a dehydrating cloth are provided on the lower surface thereof. Automatic cement roof tile manufacturing equipment with a vertically movable mold frame around the fixed lower mold,
In addition, cement, aggregate such as silica sand, and if necessary, reinforcing fibers are mixed with a large amount of water in a stoichiometric amount or more necessary for hardening of cement to form a slurry state or a soft block state with excellent fluidity. The resulting cement-based composition is used as a forming raw material. As shown in FIG. 7, the forming raw material 101 is dropped onto a lower mold 102, and the upper mold 103 and the lower mold 102 are closed and pressed. The mold is filled with the molding raw material 101, and excess water is removed through a dehydration process of suction dehydration from a suction hole (not shown) provided in the upper mold 103 to obtain a dense and complicated molded product. There is.

On the other hand, the latter method is, for example, cement,
Using a cementitious composition having poor fluidity, which is a mixture of an aggregate, a reinforcing fiber, and a water-soluble polymer in water in an amount close to the stoichiometric amount required for hardening cement, as a forming raw material, as shown in FIG. This molding raw material 201 is supplied onto the lower mold 202 and press-molded between the upper mold 203 and the lower mold 202 while applying vibration to obtain a dense cement compact.

[0005]

[Problems to be Solved by the Invention] However, the above 2
The kinds of methods have the following problems. That is, in the former method of passing through the dehydration step, since the molding raw material 101 has fluidity, it is easy to supply the raw material to the lower mold 102 and the molding raw material 101 can be easily detailed even in a complicated mold shape. Although it has the advantage of being spread, it remains as voids in the molded body where the water escape path at the time of dehydration was obtained, and since it could not be dehydrated to the stoichiometric amount, excess water remained in the molded body, There is a limit to the densification of.

On the other hand, in the latter method which does not pass through the dehydration step, since the forming raw material 201 contains only a small amount of water close to the stoichiometric amount necessary for hardening the cement, almost no water passage or surplus water is contained. Although it does not exist, a very dense molded body can be obtained, but since the flowability of the molding raw material 201 is inferior, when molding a complicated shape such as a deep wave shape,
There was a problem that the molding raw material 201 was stretched out at the time of pressing and small cracks were formed.

The present invention solves the above-mentioned conventional problems and uses a hydraulic inorganic composition mixed with a stoichiometric amount of water as a molding raw material to form a complicated molded product having a corrugated shape. It is intended to provide a method for press-molding a cement molded product, which can be molded without causing elongation and elongation of a molding raw material at the time of pressing even when molding a cement molded product. .

[0008]

In order to achieve such an object, the invention described in claim 1 (hereinafter, referred to as "first invention").
The method of press-molding a cement molded product according to
In a method of press-molding a cement-molded product, in which a raw material composed of a cement-based composition containing water in a stoichiometric amount necessary for hardening of cement is press-molded between upper and lower molds, the cement-based composition was formed into a plate shape. A belt conveyor on which the plate-shaped raw material is placed is exposed to the upper side of the lower mold, while the plate-shaped raw material is fed from the tip of the conveyor belt by the belt conveyor, this belt conveyor is at substantially the same speed as the plate-shaped raw material conveying speed. After moving the plate-shaped raw material to a desired position of the lower mold by moving it in a direction opposite to the feeding direction of the plate-shaped raw material,
It was configured to be press-molded.

Further, the method for press-molding a cement molded product according to the invention described in claim 2 (hereinafter referred to as "second invention") is a method of pressing a belt conveyor by a pressing jig in addition to the constitution of the first invention. The plate-shaped raw material was transferred from the belt conveyor to the lower mold while the plate-shaped raw material was pressed from the upper side by the portion fed from the tip to deform the plate-shaped raw material along the lower mold surface.

In the above-mentioned constitution of the present invention, as the forming raw material, in addition to cement and water, for example, a water-soluble polymer substance, an inorganic filler, a reinforcing fiber and the like can be appropriately added. The cement used in the present invention is not particularly limited, but for example, plain cement such as ordinary Portland cement, special Portland cement, alumina cement and Roman cement, acid cement, fire resistant cement, special cement such as water glass cement, gypsum and lime. , And magnesia cement, etc., and portland cement and alumina cement are preferably used in terms of strength and water resistance. These may be used alone or in combination of two or more.

The water-soluble polymer substance is not particularly limited, but examples thereof include cellulose ethers such as methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose and hydroxypropyl methyl cellulose, polyvinyl alcohol, polyacrylic acid, lignin sulfonate. Can be mentioned.

The inorganic filler is not particularly limited, but examples thereof include aggregates for cement mortar such as silica sand and river sand, admixtures for mixed cement such as fly ash, silica flower, silica fume, bentonite and blast furnace slag, sepiolite, Examples include wollastonite, natural minerals such as mica, calcium carbonate, and diatomaceous earth.
Further, for the purpose of reducing the weight, silica foam, perlite, fly ash balloon, shirasu balloon, glass balloon, inorganic foam such as foamed clay may be used. These may be used alone or 2
You may use together 1 or more types.

The reinforcing fiber is not particularly limited,
For example, synthetic fibers such as vinylon, polyamide, polyester, polypropylene and aramid, inorganic fibers such as glass, potassium titanate and steel, natural fibers such as pulp and hemp can be used. The method of supplying the molding raw material onto the belt conveyor is not particularly limited, but for example, the cement composition that has been mixed and kneaded in advance is discharged from the raw material feeder onto the belt conveyor, and the desired molding of the molded product to be molded is performed. There is a method of cutting at a fixed position such as near the opening at the tip of the raw material feeder with a length commensurate with the weight of the product.

Further, the size of the plate-shaped raw material needs to be substantially along the entire mold surface of the lower mold since it hardly requires flow at the time of pressurization, but the discharge width of the raw material feeder and the molding die,
It can be appropriately determined from the product shape. The feeding speed of the plate-shaped raw material is determined by the hardness of the raw material and the moving speed of the belt conveyor.

The pressing jig is not particularly limited, but a roll-shaped jig is preferable, and the pressing jig may be provided separately from the belt conveyor or may be provided integrally with the belt conveyor. The device for moving the belt conveyor to the lower mold is not particularly limited,
Examples include hydraulic piston cylinders and pneumatic piston cylinders.

The cement molded product obtained by the molding method of the present invention is not particularly limited, but after curing and curing for a certain period of time under a predetermined condition, a desired coating or the like is applied to the surface portion if necessary. You may do so.

[0017]

According to the structure of the first invention, first, the belt conveyer on which the plate-shaped raw material is placed is exposed to the lower mold. Then, while the plate-shaped raw material is being sent out by the belt conveyor, the belt conveyor is moved at the same speed as the sending speed in the direction opposite to the sending direction. By this movement, the plate-shaped raw material is transferred to the lower mold while being deformed by its own weight so as to be along the mold surface of the lower mold. Then, when the plate-shaped raw material is completely transferred to the lower mold, the upper mold and the lower mold are closed and press-molded at a predetermined pressure. At this time, since the plate-shaped raw material is along the mold surface of the lower mold,
It is pressed in the mold cavity without much movement in the mold cavity. Therefore, the plate-shaped raw material is molded into a molded product having no small cracks due to the raw material being completely stretched.

On the other hand, according to the structure of the second invention, the portion of the plate-shaped raw material sent out from the belt conveyor is sequentially pressed by the pressing jig from the upper side to the mold surface of the lower die, so that the plate-shaped raw material is deformed by its own weight. Not only that, it is forcibly deformed by the holding jig so as to follow the mold surface of the lower mold.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. 1 to 5 show one embodiment of a method for press-molding a cement molded product according to the first invention in the order of steps. As shown in FIGS. 1 to 5, the molding apparatus 1 used in this embodiment includes a press machine (press piston) 2, an upper mold 3, a lower mold 4, a raw material feeder 5, and a belt. And a conveyor 6.

Known press molding machines 2, upper mold 3 and lower mold 4 are used. Raw material feeder (kneading extruder) 5
In the above, the cement-based composition 8a mixed and kneaded in advance is introduced from the hopper 51, the cement-based composition 8a is further kneaded, and then discharged from the discharge port 52 to a predetermined thickness and width. Further, in front of the discharge port 52, a cutting machine 9 for cutting the discharged plate-shaped cementitious composition 8a is provided.

The belt conveyor 6 is adapted to rotate in the direction of arrow A, and is connected to the piston 11 of the hydraulic cylinder 10. The expansion and contraction of the piston 11 causes the upper part of the lower mold 4 and the raw material feeder 5 to move. It is freely movable between. That is, according to the method of this example, a molded product can be molded as follows.

As shown in FIG. 1, the cementitious composition 8a
Is discharged from the discharge port 52 of the raw material supply device 5 to have a predetermined thickness and width. At this time, the belt conveyor 6 rotates in the direction of arrow A according to the discharge speed of the cementitious composition 8a. When the cement composition 8a corresponding to the weight of the obtained molded product is discharged, as shown in FIG.
The cementitious composition 8a is cut to obtain a plate-shaped raw material 8.

As shown in FIG. 3, the hydraulic cylinder 10
The belt conveyor 6 is exposed above the lower mold 4 by extending the piston 11 of. As shown in FIG. 4, while rotating the belt conveyor 6 in the direction of arrow A to feed the plate-shaped raw material 8 from the belt conveyor 6, the piston 11 of the hydraulic cylinder 10 is retracted at the same speed as the feeding speed of the plate-shaped raw material 8. Let

As a result, as shown in FIG. 4, the plate-shaped raw material 8 is transferred to the lower die 4 while being deformed by its own weight along the die surface 41 of the lower die 4. And belt conveyor 6
Is, as shown in FIG. 5, the discharge port 52 of the original raw material feeder 5.
Return to the forward position. The upper mold 3 is lowered and press-molded at a predetermined pressure.
Since the plate-shaped raw material 8 is along the mold surface 41 of the lower mold 4 in advance, it is pressed in the mold cavity without largely moving in the mold cavity. Therefore, even when the cement-based composition 8a having a small amount of water and poor fluidity is used, the molded product can be molded without causing extension cracks and small cracks.

The obtained molded product is demolded by a known method, then cured and cured, and the surface thereof is subjected to a cosmetic treatment such as painting if necessary. Incidentally, as the cementitious composition 8a to be the plate-shaped raw material 8, for example, 100 parts by weight of ordinary Portland cement, 40 parts by weight of silica stone powder (Blaine value 6000, average particle size 40 μm), vinylon fiber (2 denier, length) 4 mm), 2 parts by weight of pulp, 33 parts by weight of water, methyl cellulose (viscosity of 2% aqueous solution at 20 ° C. 30
000 cps) (2 parts by weight) is mixed in a mixer (Eirich mixer RVO2) for 10 minutes, and further mixed with a water amount close to the stoichiometric amount kneaded with a kneader, which has poor fluidity.

FIG. 6 shows an embodiment of a method for press-molding a cement molded product according to the second invention. That is, in this molding method, as shown in FIG. 6, a roll 7 as a pressing jig is integrally provided on the belt conveyor 6, and the belt conveyor 6 is rotated in the arrow A direction in the step of the first invention. While feeding the plate-shaped raw material 8 from the belt conveyor 6, the piston 11 of the hydraulic cylinder 10 is retracted at the same speed as the feeding speed of the plate-shaped raw material 8, and at the same time, the portion of the plate-shaped raw material 8 fed from the belt conveyor 6 is removed. The molding method is the same as that of the first invention except that the mold surface 41 of the lower mold 4 is pressed by the roll 7.

That is, according to this method, the plate-shaped raw material 8
While deforming from the belt conveyor 6 under its own weight, the lower mold 4
At the same time, the roll 7 is forced to further deform along the mold surface 41, so that the mold shape is complicated, and the plate-shaped raw material 8 only needs to adjust the rotation speed of the conveyor and the moving speed of the entire conveyor. Then, even if the mold surface of the lower mold 4 cannot be sufficiently filled, the plate-shaped raw material 8 can be made to fit the mold surface 41 of the lower mold 4 exactly.

The method for press-molding a cement molded product according to the present invention is not limited to the above-mentioned embodiments. For example, in the above-mentioned examples, the cementitious composition is mixed and kneaded in advance and fed into the raw material feeder from the hopper, but a raw material feeder having a mixing and kneading function may be used. Absent.

In the above-mentioned embodiment, the plate-shaped cement composition is discharged from the raw material feeder onto the belt conveyor and then cut, and the plate-shaped raw material is placed on the belt conveyor. Alternatively, the plate-shaped raw material may be preliminarily formed in a desired size at another place and placed on the belt conveyor. As the cementitious composition used in the present invention, it is possible to mold a product having a more complicated shape by using a cementy composition having a certain fluidity and containing more water than the stoichiometric amount. In this case, known dehydration methods may be combined.

[0030]

Since the method for press-molding a cement molded product according to the first and second aspects of the present invention is configured as described above, it is close to the stoichiometric amount which has conventionally caused elongation and the like during press-molding. Even if a hydraulic inorganic composition containing only water is used as a molding raw material, a compact and excellent appearance can be molded without causing the molding raw material to stretch.

Moreover, even a complicated shape such as a corrugated shape can be formed into a compact and excellent in appearance.
In particular, according to the method of the second aspect of the invention, the mold shape is complicated and the plate-shaped raw material can be exactly aligned with the mold surface of the lower mold. That is, a molded product having a complicated shape can be molded more reliably.

[Brief description of drawings]

FIG. 1 is an explanatory view showing one example of a method for producing a cement molded product according to the first invention and showing a step of supplying a cement composition to a belt conveyor thereof.

FIG. 2 is an explanatory diagram showing a step subsequent to the step of FIG.

FIG. 3 is an explanatory diagram showing a step subsequent to the step of FIG.

FIG. 4 is an explanatory diagram showing a step that follows the step of FIG.

5 is an explanatory diagram showing a step subsequent to the step in FIG. 4. FIG.

FIG. 6 is an explanatory view illustrating one embodiment of the method for producing a cement molded product according to the second invention.

FIG. 7 is a cross-sectional view showing a raw material supply state when a conventional dehydration process is performed.

FIG. 8 is a cross-sectional view showing a raw material supply state when a conventional dehydration step is not performed.

[Explanation of symbols]

 3 Upper mold 4 Lower mold 6 Belt conveyor 7 Roll (holding jig) 8 Plate-shaped raw material

Claims (2)

[Claims] 1. A method for press-molding a cement-molded product, comprising press-molding a raw material comprising a cement-based composition containing water in a stoichiometric amount required for hardening cement between upper and lower molds, wherein the cement-based composition comprises Belt conveyor on which the plate-shaped raw material is placed, facing the upper part of the lower mold, while sending the plate-shaped raw material from the tip of the conveyor belt by the belt conveyor, this belt conveyor convey speed of the plate-shaped raw material After pressing the plate-shaped raw material to a desired position of the lower mold by moving the plate-shaped raw material in a direction opposite to the feeding direction of the plate-shaped raw material at substantially the same speed, press-molding the cement molded product . 2. A plate-shaped raw material is pressed from the upper side by a portion fed from the tip of the belt conveyor by a pressing jig to deform the plate-shaped raw material along the lower mold surface, and the plate-shaped raw material is fed from the belt conveyor. The method for press-molding a cement molded article according to claim 1, wherein the cement is transferred to a lower mold.